Our investigations were performed in a Hungarian large-scale pig farm in Hajdú-Bihar County, where pork production, its conditions and key indicators were studied. Data were collected by questionnaires, interviews and methodical observations. Our estimation was prepared by one of the non-parametric forms of Survival Analysis, the Kaplan-Meier analysis. Mortality intensity was quantified by one of the other models of Survival Analysis, the log-rate exponential model. We find that the most significant culling reasons: due to abortion, lack of being heat for pregnancy test, low farrowing performance. As a conclusion we can state that production efficiency can be increased in a fattening pig farm if the farrowing numbers of sows are taken into consideration and the place of cost minimum is calculated by the input prices of the given period. By this the optimal point of time as long as sows are worth keeping in production, can be calculated. Therefore, considerable cost savings can be attained on a big farm.